The first add-on, Bug Hunt, is all about cooperative multiplayer and tasks players with taking on increasingly difficult waves of enemies across three new maps. These maps are based on the Aliens films and Bug Hunt is slated for March.
The remaining three add-ons are scheduled to be available by the end of August.
Each game add-on can be bought separately or as part of the Season Pass Bundle for $29.99/2400 MS Points saving you 40%. You can now purchase the pass through Steam, and soon through PSN and XBL.
Aliens: Colonial Marines is out February 12 for PC, PS3, and Xbox 360 and the Wii U version is expected before the end of March.